Prediction of Water Distribution System Contamination Based on Wildfire Burn Severity in Wildland Urban Interface Communities
Stefanie Schulze, Erica C. Fischer
Abstract
The devastation to infrastructure in wildland urban interface (WUI) communities caused by wildfires has brought attention to the dramatic and unforeseen impacts of high fuel load density within these communities. In the past three years, above-ground structures have been damaged by wildfire and fire damage to underground water distribution system components has caused contamination of the drinking water in affected areas. To quantify the potential water contamination risks posed by wildfire hazards on WUI communities, the risk is assessed on the basis of burn severity. This study found that traditional methods of calculating burn severity using satellite imagery were not appropriate for classifying localized burn severity within WUI communities. Instead, local burn severity within WUI communities can be quantified by the density of damaged structures. This research uses water sampling data and results from the City of Santa Rosa and the Town of Paradise to develop fragility functions for estimating the probability of a water sample exceeding California maximum contaminant levels given the number of damaged structures surrounding the sample location. Results of this research will provide useful information for WUI water utilities regarding the implementation of mitigation strategies and location of vulnerabilities throughout their water distribution systems to minimize damage.